Blog

Understanding IP Addresses – IPv4 vs IPv6

Internet Protocol (IP) Addresses are one of the fundamental components that enable computer networks (including the Internet) to operate effectively. They provide the means for a variety of devices (e.g. routers, laptops, computers, servers, hosts, smartphones, tablets, printers, gaming consoles etc.) to accurately find and communicate with each other across a given network.

What is an IP Address?

“An IP Address is a unique identifier for any device connected to a computer network such as the Internet.”

Currently there are two versions of IP addresses in use today:
• IP Version 4 (IPv4)
• IP Version 6 (IPv6)

IP Version 4 (IPv4)

IPv4 was first deployed on January 1, 1983 and is still the most common format currently in use today. IPv4 addresses are displayed in a dotted-decimal format that contains four octets with numbers ranging between 0 – 255 (e.g. 54.225.229.200).

Based on this quad-dotted notation there are two simple methods to determine the total number of possible IPv4 addresses.

Method 1: – Simple combination with replacement
An IPv4 Address is made up of 4 numbers, each between 0 and 255. Including the 0 there are 256 possible combinations (0, 1, 2 … 254, 255) in each part. Thus, the total number of combinations is calculated as:
=> 256 x 256 x 256 x 256
=> 2564
= 4,294,967,296 (approx. 4.3 billion)

In total, based on the quad-dotted notation there are approximately 4.3 billion possible IPv4 combinations. However, almost 600 million IPv4 addresses have been reserved for special purposes, allowing approximately 3.7 billion left for general usage.

IP Address shortage

There are currently billions of devices connected to the Internet making it the world’s largest integrated network. This number is set to grow substantially over the coming years with the increasing proliferation of internet capable smart devices and machines (e.g. televisions, air conditioners, washing machines, lights, cars etc.). All will have to connect and communicate through some form of IP Address.

While 3.7 billion unique combinations might sound like a lot, the huge growth in internet connected devices has already led to the virtual depletion of available IPv4 addresses. This prompted the introduction of the latest address standard – IPv6.

IPv6 addresses are considerably different in their appearance as compared to IPv4. They can include up to 8 segments, with each containing a hexadecimal string of values between 0 and FFFF. Each of the segments is separated by a colon (e.g. 2001:0DB8:7AAB:0008:0000:0000:A573:2618).

IPv6 addresses can also be written in short form where segments are zero or contain leading zeros. For example:
=> 2001:0DB8:7AAB:0008:0000:0000:A573:2618 (full IPv6 Address)
=> 2001:0DB8:7AAB:0008::A573:2618 (after compressing zero value segments)
=> 2001:DB8:7AAB:8::A573:2618 (after further compressing leading zeros)

Although there are many other differences between IPv4 and IPv6, one of the primary advantages is an exponentially larger number of available IP addresses. So how many IPv6 combinations are available?

Thus there are approximately 3.4028 x 1038 (that’s a lot) of IPv6 Address combinations.

IPv6 – The past, the present and the future

IPv6 was originally released in 1999 but its widespread deployment has been relatively slow. In the last 6 months the levels of IPv6 connectivity among Google users has risen from just 1.07% to 1.45% (see graph below).

One of the challenges in moving toward IPv6 is that it is not easily interchangeable with an existing IPv4 address. Consequently, Internet Service Providers (ISP’s) cannot simply switch over to the new IPv6 address overnight. That process is likely to take many years.

In the meantime, with the virtual depletion of IPv4 combinations major ISP’s, device manufacturers and web companies around the world have been enabling their products to support both IPv4 and the more numerous IPv6 protocol.

Although total IPv6 traffic is still relatively low, over the last 6 months its usage has increased 35.51% (1.07 – 1.45%). This trend is likely to continue well into the future as IPv6 (very) slowly but surely becomes more dominant and (eventually) replaces IPv4.